From Team Fortress Wiki
The PDAs are default weapons for the Engineer, consisting of the Build Tool and Demolish Tool, which he uses to construct and destroy his various buildings respectively. The Build Tool is a calculator-type device, whereas the Demolish Tool looks similar to a typical hand-held detonation device with a miniature screen and large red button.
These gadgets are not regular weapons as they cannot be used to attack; they mainly serve as a visual cue to the player and those that see the player's character. Therefore, switching between PDAs and the last weapon active does not result in the usual delay caused by weapon switching. While the player is using the PDA, a unique menu appears on-screen to allow the player to build or destroy available buildings.
Upon selecting one of the PDAs, a superimposed HUD appears in the middle of your view. Though it lists all four available buildings, only the highlighted choices will be selectable. Selection of the buildings is done through the preset numbered keys. Pressing the last weapon used key or primary fire key will cancel the PDA and return to the previous weapon. The Pip-Boy changes the look of the Build and Destroy Tools.
The selection keys will only function on the appropriate PDA under the right conditions. Should the player have insufficient Metal, they will be denied access to certain buildings on the Build Tool, yet gathering Metal will re-enable the choices with the cost met. Conversely, the Demolish Tool will only destroy builds that have already been constructed. The Demolish Tool cannot be used to destroy buildings currently being sapped by the Sapper.
If a player chooses to construct an available building from the Build Tool, the player model will then hold a Toolbox and the player will see a template on the ground in front of them showing the orientation of the chosen building. While the template is visible, secondary fire adjusts the building's orientation by 90 degrees counter-clockwise, whilst primary fire starts the build. The last weapon used button cancels the build.
Note: The console versions do not have a separate Demolish Tool. Instead, both are handled by the Build Tool, serving as a single PDA. After choosing the proper weapon slot to activate the PDA, the player uses the right trigger or 'R2' to construct the selected building if enough Metal is available, and the left trigger or 'L2' to demolish the selected building if it has already been built.
- Fixed some truncated strings in the destroy menu
- Changed PDA menus to accept keys bound to "slot1", "slot2", etc., and "slot10" cancels
- Fixed Engineer being able to detonate buildings that are being sapped.
- [Undocumented] Added Construction PDA slot to the Engineer's loadout screen.
- [Undocumented] Made the Construction Tool nameable.
- [Undocumented] Construction Tool and Demolish Tool now appear in backpack when viewing stock items.
- There is a PDA Token in
items_game.txt, but it is unused. Internally, the Engineer's Build Tool and the Spy's Disguise Kit fall under this slot.
- The PDA2 token is used for crafting the Spy's unlockable watches, which fall into the PDA2 slot, and can be made by crafting together 3 Spy watches. This is the only use for the token.
exec 360controlleris enabled through the console, the PDA acts as both a build and demolish tool.
- Despite showing amongst other stock items that are usable with a Name Tag or Description Tag, both the Demolish Tool and the Disguise Kit do not work with the Name Tag or Description Tag.
Build Tool RED first-person view with the Gunslinger equipped.
Build Tool BLU first-person view with the Gunslinger equipped.
Demolish Tool RED first-person view with the Gunslinger equipped.
Demolish Tool BLU first-person view with the Gunslinger equipped.
Toolbox RED first-person view with the Gunslinger equipped.
Toolbox BLU first-person view with the Gunslinger equipped.
Build Tool: Menu with the Pip-Boy equipped.